Over the past several years, vehicle seat heating has become increasingly popular in improving the comfort of vehicle seats. Typically, seat heating is provided by one or more heating mats positioned within the seat. Some designers have suggested the use of channels within the seat through which heated air passes for heating the surface of the seat. Additionally, it is known to introduce air into the seat and to permit the air to exit out of the seat against the support surface in order to achieve a cooling effect. However, the draft produced in this manner may be considered uncomfortable and undesirable for the occupant. Also, if the air is discharged directly toward the user, the user will generally block any air holes, which prevents cooling and can lead to user perspiration and dampening of clothes.
U.S. Pat. No. 4,685,727 suggests a configuration in which a large air channel is formed directly behind the vehicle seat trim cover, and air is flown through the channel for drawing moisture away from the trim cover surface for improving occupant comfort. However, only limited transfer of heat and moisture through the trim cover is possible with such a configuration because the air flow is adjacent to the rear surface and no significant pressure differential is created between the channel and the trim cover surface. Furthermore, positioning the channel directly behind the trim cover affects occupant comfort, and therefore must be compensated by appropriate support structure vertically and laterally along the seat, as described in the '727 patent.
Accordingly, it is desirable to provide a seat ventilation system for drawing heat and moisture away from the surface of the seat in a manner in which an increased amount of heat and moisture can be drawn from such surface, and large, uncushioned channels are not required within the seat which adversely affect the support structure of the seat, thus requiring additional support structure, which adds cost to the seat.